A Sample and Hold Time-to-Amplitude Converter for single photon time-of-flight measurement

A novel Time-to-Amplitude Converter (TAC) based on Sample and Hold (S/H) principle is presented for single photon time-of-flight (TOF) measurement. With a high fill factor as much as 34% for a single photon avalanche diode (SPAD) pixel, the designed TAC offers the potential to realize high-density time-correlated single photon counting (TCSPC) detectors. Post-layout simulation reveals that time resolution of 195 ps LSB is obtained over a 100 ns time full-scale range (FSR). Furthermore, the TAC is characterized by a low differential nonlinearity (DNL) of 0.25% LSB and a low integral nonlinearity (INL) of 0.15 LSB in the whole detectable time range.